Heat exchanger, refrigeration cycle device equipped with heat exchanger, or heat energy recovery device

ABSTRACT

A plurality of heat-exchanger tubes, each of which has an inlet fin formed on a side surface on the air inlet side of a flattened hollow tube and extending upstream of air along the flow of air and an outlet fin formed on the side surface on the air outlet side of the hollow tube and extending downstream of the air along the flow of the air are arranged at regular intervals in such a manner that their oblong planes face one another, an upper header which supplies a first heat exchange medium is attached on top of the heat-exchanger tubes, and an lower header which collects the first heat exchange medium is attached at the bottom of the heat-exchanger tubes to form a heat exchanger.

TECHNICAL FIELD

The present invention relates to a heat exchanger, a refrigeration cycle device equipped with the heat exchanger, or a heat energy recovery device and, in particular, to a heat exchanger that uses a first heat exchange medium flowing through a plurality of heat-exchanger tubes and a second heat exchange medium flowing between the plurality of heat-exchanger tubes in a direction orthogonal to the flow of the first heat exchange medium, and to a refrigeration cycle device, such as a room air conditioner, an all-in-one air conditioning system, a refrigerating machine, and a car air conditioner, that uses such heat exchanger in a refrigeration cycle, or a heat energy recovery device that uses such heat exchanger in recovering heat energy produced in an engine or a fuel cell.

BACKGROUND ART

A heat exchanger of this type that has been proposed in the past includes a plurality of flattened tubes, corrugated fins folded into wrinkles and provided between the tubes, an inlet tank attached to the upper ends of the plurality of tubes to supply a cooling medium to the tubes, and an outlet tank attached to the lower ends of the plurality of tubes to collect the cooling medium from the tubes, and cools the cooling medium by heat exchange between ambient air blown into spaces between the tubes and the cooling medium (see Patent Literature 1, for example). In this heat exchanger, the corrugated fins provided between the tubes increase heat transfer surface area so as to supplement the heat transfer performance of air which has a low heat transfer coefficient.

A finless micro heat exchanger has been proposed that includes a plurality of flattened heat-exchanger tubes formed by bending a metal plate having a thickness of less than or equal to 0.1 mm to have a cross section of less than or equal to 0.5 mm, inner fins provided in the heat-exchanger tubes, and headers that are attached to the upper and lower ends of each of the heat-exchanger tubes spaced at a pitch in the range of two to four times the thickness, 0.5 mm, of the heat-exchanger tubes to supply a cooling medium to the tubes, and cools the cooling medium by heat exchange between ambient air flowing between the plurality of tubes and the cooling medium (see Patent Literature 2, for example). In this heat exchanger, the heat-exchanger tubes are made from a thin plate of a metal that has high heat transfer characteristics with the aim of achieving size reduction and improved heat exchange efficiency and the inner fins are provided to prevent deformation of the heat-exchanger tubes formed from the thin plate under the pressure of the cooling medium.

SUMMARY OF INVENTION Technical Problem

When the former heat exchanger described above is reduced in size, contaminants, dust and frost are deposited on the corrugated fins inhibiting the flow of air and decrease the efficiency of heat exchange. Furthermore, when this heat exchanger is used as a small evaporator or exhaust heat recovery device, the corrugated fins inhibit discharge of condensate water and further decrease the efficiency of heat exchange.

In the latter finless micro heat exchanger, when wall thickness of the heat-exchanger tubes is further reduced in order to increase the heat exchange efficiency, the heat-exchanger tubes are deformed under the pressure of the cooling medium and inhibit the flow of air between the heat-exchanger tubes and reduce the condensate water discharge capacity. In addition, the thinning of the walls decreases corrosion resistance.

A principal object of a heat exchanger of the present invention is to improve the heat exchange efficiency of a small heat exchanger. A principal object of a refrigeration cycle device equipped with the heat exchanger, or a heat energy recover device, is to improve the heat exchange efficiency of the device.

Solution to Problem

To achieve the principal objects described above, a heat exchanger, a refrigeration cycle device equipped with the heat exchanger, or a heat energy recover device has adopted the following design.

A first heat exchanger of the present invention includes a plurality of heat-exchanger tubes which are made of a metal into flattened hollow tubes and are arranged in parallel to one another in such a manner that oblong planes face one another and performs heat exchange by using a first heat exchange medium flowing through the plurality of heat-exchanger tubes and a second heat exchange medium flowing between the plurality of heat-exchanger tubes in a direction orthogonal to the first heat exchange medium;

wherein the plurality of heat-exchanger tubes has inlet fins extending upstream along a flow of the second heat exchange medium from a side surface on the inlet side of the second heat exchange medium.

In the first heat exchanger of the present invention, since the inlet fins extending upstream along the flow of the second heat exchange medium from the side surface on the inlet side of the second heat exchange medium is formed in the plurality of heat-exchanger tubes, the heat transfer surface area is increased to improve the heat exchange efficiency of the heat exchanger. In addition, since the spacing between adjacent inlet fins is wider than the spacing between adjacent heat-exchanger tubes by an amount equivalent to the thickness of each tube, condensate water can be discharged at a high rate and decrease in the heat exchange efficiency due to deposition of contaminants, dust and frost which could hamper the flow of air can be prevented when the heat exchanger is used as an evaporator or an exhaust air recovery device. Moreover, since these improvements can be achieved simply by forming the inlet fins, increase in weight of the heat exchanger and increase in complexity of fabrication and assembly of the heat exchanger can be prevented. Accordingly, a small heat exchanger having high heat exchange efficiency can be implemented.

In a first heat exchanger of the present invention described above, the inlet fins may be integral with a member that constitutes the heat-exchanger tubes. This enables the inlet fins to be formed simultaneously with the heat-exchanger tubes and also enables the heat-exchanger tubes having the inlet fins to be readily formed. This also can further improve the heat transfer from the heat-exchanger tubes to the inlet fins.

In a first heat exchanger of the present invention, the heat-exchanger tubes may include an inner fin inside the tubes and the inlet fin may be integral with the inner fin. This facilitates formation of the inlet fins and can further improve the heat transfer characteristics of the inlet fins.

Furthermore, in the first heat exchanger of the present invention, a wavelike ridges and grooves where a series of “V” shape peaks and valleys of a wave runs viewed from the upstream side of the flow of the second heat exchange medium may be formed in the oblong planes of the inlet fins and/or the heat-exchanger tubes. This enables a stream (a secondary stream) different from a main stream of the second heat exchange medium flowing between adjacent inlet fins and adjacent heat-exchanger tubes to be smoothly formed near the oblong planes of the inlet fins and/or the heat-exchanger tube, and the secondary stream can improve the heat transfer efficiency.

Alternatively, in a first heat exchanger of the present invention, the plurality of heat-exchanger tubes may have outlet fins extending downstream along the flow of the second heat exchange medium from a side surface on the outlet side of the second heart exchange medium. This can further increase heat transfer surface area to improve the heat exchange efficiency of the heat exchanger. In this case, the outlet fin may be integral with a member that constitute each heat-exchanger tube. This enables the outlet fins to be formed simultaneously with the heat-exchanger tubes and also enables the heat-exchanger tubes having the outlet fins to be readily formed. This also can further improve the heat transfer from the heat-exchanger tubes to the outlet fins. Alternatively, the outlet fins may be integral with the inner fins. This can facilitate formation of the outlet fins and further improve the heat transfer characteristics of the outlet fins.

A second heat exchanger of the present invention includes a plurality of heat-exchanger tubes which are made of a metal into flattened hollow tubes and are arranged in parallel to one another in such a manner that oblong planes face one another and performs heat exchange by using a first heat exchange medium flowing through the plurality of heat-exchanger tubes and a second heat exchange medium flowing between the plurality of heat-exchanger tubes in a direction orthogonal to the first heat exchange medium;

wherein the plurality of heat-exchanger tubes has outlet fins extending downstream along a flow of the second heat exchange medium from a side surface on the outlet side of the second heat exchange medium.

In the second heat exchanger of the present invention, since the outlet fins extending downstream along the flow of the second heat exchange medium from the side surface on the outlet side of the second heat exchange medium is formed in the plurality of heat-exchanger tubes, the heat transfer surface area is increased to improve the heat exchange efficiency of the heat exchanger. In addition, since the spacing between adjacent outlet fins is wider than the spacing between adjacent heat-exchanger tubes by an amount equivalent to the thickness of each tube, condensate water can be discharged at a high rate and decrease in the heat exchange efficiency due to deposition of contaminants, dust and frost which could hamper the flow of air can be prevented when the heat exchanger is used as an evaporator or an exhaust heat recovery device. Moreover, since these improvements can be achieved simply by forming the outlet fins, increase in weight of the heat exchanger and increase in complexity of fabrication and assembly of the heat exchanger can be prevented. Accordingly, a small heat exchanger having high heat exchange efficiency can be implemented.

In the first and second heat exchangers according to the embodiment of the present invention described above, the heat-exchanger tubes are formed to have a thickness of less than or equal to 2 mm and are arranged in parallel to one another with a regular spacing of less than or equal to 2 mm between adjacent heat-exchanger tubes. In particular, any of the first and second heat exchanges may be a small heat exchanger with a plurality of heat-exchanger tubes each of which is formed as a flattened hollow tube (for example a hollow tube that is formed from a 0.25-mm thick aluminum thin plate and has a thickness of less than or equal to 1 mm or a hollow tube that is made from a 0.1-mm thick stainless-steel thin plate and has a thickness of less than or equal to 0.5 mm) by stamping, bending and brazing of a thin plate of a metal having good heat transfer characteristics (for example a 0.25-mm thick aluminum thin plate or a 0.1-mm thick stainless-steel thin plate).

Any of the first and second heat exchangers according to the embodiment of the present invention described above can be used as a refrigeration cycle heat exchanger of a refrigeration cycle device that has a refrigeration cycle, such as a room air conditioner, an all-in-one air conditioning system, a refrigerating machine, or a car air conditioner. Furthermore, any of the first and second heat exchangers according to the embodiment of the present invention described above can be used as a heat exchanger in a heat energy recovery device that recovers heat energy produced in an engine or a fuel cell.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram schematically illustrating a configuration of a heat exchanger 20 as one embodiment of the present invention;

FIG. 2 is a diagram schematically illustrating a configuration of a heat-exchanger tube 30;

FIG. 3 is a cross-sectional view of the heat-exchanger tube 30, taken along plane A-A in FIG. 2;

FIG. 4 is a diagram illustrating how the heat-exchanger tube 30 is assembled;

FIG. 5 is a diagram illustrating arrangement of adjacent heat-exchanger tubes 30;

FIG. 6 is a cross-sectional view of a heat-exchanger tube 30B according to a variation;

FIG. 7 is a cross-sectional view of a heat-exchanger tube 30C according to a variation;

FIG. 8 is a cross-sectional view of a heat-exchanger tube 30D according to a variation;

FIG. 9 is a cross-sectional view of a heat-exchanger tube 30E according to a variation;

FIG. 10 is a cross-sectional view of a heat-exchanger tube 30F according to a variation;

FIG. 11 is a cross-sectional view of a heat-exchanger tube 30G according to a variation;

FIG. 12 is a cross-sectional view of a heat-exchanger tube 30H according to a variation;

FIG. 13 is a cross-sectional view of a heat-exchanger tube 30J of according to a variation;

FIG. 14 is a cross-sectional view of a heat-exchanger tube 30K according to a variation;

FIG. 15 is a cross-sectional view of a heat-exchanger tube 30L according to a variation;

FIG. 16 is a cross-sectional view of a heat-exchanger tube 30M according to a variation;

FIG. 17 is a cross-sectional view of a heat-exchanger tube 30N according to a variation;

FIG. 18 is a cross-sectional view of a heat-exchanger tube 30P according to a variation;

FIG. 19 is a cross-sectional view of a heat-exchanger tube 30Q of according to a variation;

FIG. 20 is a diagram schematically illustrating a configuration of a heat exchanger 220 according to a variation;

FIG. 21 is a diagram schematically illustrating a configuration of a heat-exchanger tube 230; and

FIG. 22 is a cross-sectional view of the heat-exchanger tube 230, taken along plane B-B in FIG. 21.

DESCRIPTION OF EMBODIMENT

A mode for carrying out the present invention will be described with respect to an embodiment.

FIG. 1 is a diagram schematically illustrating a configuration of a heat exchanger 20 as one embodiment of the present invention. As illustrated, the heat exchanger 20 of the embodiment includes a plurality of heat-exchanger tubes 30 arranged in parallel to one another with a regular spacing in such a manner that oblong planes face one another, an upper header 22 which is attached to the upper ends of the plurality of heat-exchanger tubes 30 and supplies a first heat exchange medium flowing in through an inlet 24 to the heat-exchanger tubes 30, and a lower header 62 which is attached to the lower ends of the plurality of heat-exchanger tubes 30 and discharges the first heat exchange medium collected from the heat-exchanger tubes 30 through an outlet 64. The heat exchanger 20 of the embodiment accomplishes heat exchange by using the first heat exchange medium flowing through the plurality of heat-exchanger tubes 30 from the top to bottom in FIG. 1 and a second heat exchange medium flowing between adjacent heat-exchanger tubes 30 in a direction orthogonal to the flow of the first heat exchange medium. Here, assuming that the heat exchanger 20 of the embodiment is used in a refrigeration cycle, the first heat exchange medium may be a fluorocarbon cooling medium and the second heat exchange medium may be air, for example. This case will be taken as an example in the following description.

FIG. 2 is a diagram schematically illustrating a configuration of a heat-exchanger tube 30 and FIG. 3 is a cross-sectional view of the heat-exchanger tube 30, taken along plane A-A in FIG. 2. As illustrated in FIGS. 2 and 3, the heat-exchanger tube 30 includes a first tube member 32 on which an inlet fin 34 is formed, a second tube member 42 on which an outlet fin 46 is formed, and an inner fin 50 formed in a wave shape. The first tube member 32 is formed from a thin plate of a metal having high heat conductivity (for example, stainless-steel or aluminum) in an open rectangular shape with a handle-like portion by processing such as stamping and bending. The second tube member 42 is made of the same material and in the same shape as the first tube member 32. The inner fin 50 is formed from a thin plate of a metal having high heat conductivity (for example stainless-steel or aluminum) like the first tube member 32 and the second tube member 42. FIG. 4 illustrates how the heat-exchanger tube 30 is assembled. As illustrated in FIG. 4, the heat-exchanger tube 30 is configured in such a manner that the inner fin 50 is placed inside the open rectangular portions of the first tube member 32 and the second tube member 42, the handle-like portions of the first tube member 32 and the second tube member 42 are located at the opposite sides, the peaks of the waved inner fin 50 are brazed to the inner walls of the rectangular portions of the first tube member 32 and the second tube member 42, and the rectangular portions of the first tube member 32 and the second tube member 42 are brazed together as illustrated.

FIG. 5 illustrates an example of the inlet fin 34 side of adjacent heat-exchanger tubes 30 formed from a 0.1-mm thick stainless-steel thin plate. Each of the heat-exchanger tubes 30 is formed from a 0.1-mm thick stainless-steel thin plate in such a manner that the oblong plane of the hollow tube has a thickness of 10.0 mm, the hollow tube has a thickness of 0.5 mm, and each of the inlet fin 34 and the outlet fin 46 has a length of 4.0 mm. The adjacent heat-exchanger tubes 30 are arranged with a spacing of 1.0 mm. As illustrated, the spacing between the hollow tubes of the adjacent heat-exchanger tubes 30 is 1.0 mm whereas the spacing between the inlet fins 34 is 1.4 mm, which is equal to 1.5 mm minus the thickness of the inlet fin 34, 0.1 mm. While the heat exchanger equipped with the heat-exchanger tubes 30 in this arrangement will be described as the heat exchanger 20 of the embodiment in the following description, it would be understood that the material and size of the heat-exchanger tubes 30 and the spacing between adjacent heat-exchanger tubes 30 are not limited to these specifics.

Functions of the heat exchanger 20 of the embodiment will be described below. As has been described above, the fluorocarbon cooling medium as the first heat exchange medium is supplied from the upper header 22 to the heat-exchanger tubes 30, flows down the heat-exchanger tubes 30 vertically, and is collected by the lower header 62. As illustrated in FIG. 1, air as the second heat exchange medium with which the fluorocarbon cooling medium exchanges heat is flown from the inlet fin 34 side of each heat-exchanger tube 30 to the outlet fin 46 side (from the front side to the back side in FIG. 1), that is, in the direction orthogonal to the flow of the fluorocarbon cooling medium. Since the temperature of the fluorocarbon cooling medium supplied to the heat exchanger 20 is lower than that of the air, heat exchange between the fluorocarbon cooling medium and the air can cause water in the air to deposit on the surface of the heat-exchanger tubes 30 as condensate water. Condensate water also deposits on the surface of the inlet fins 34, but because the spacing between the inlet fins 34 of the adjacent heat-exchanger tubes 30 (1.4 mm) is greater than the spacing between the hollow tube portions (1.0 mm) in the heat-exchanger tubes 30 of the embodiment as illustrated in FIG. 5, the condensate water is more smoothly discharged downward through the spacing between the inlet fins 34 than through the spacing between the hollow tube portions and thus clogging due to condensate water is prevented.

In the heat exchanger 20 of the embodiment described above, since the inlet fin 34 is formed on the side surface of each heat-exchanger tube 30 on the air inlet side (the side surface of the hollow tube portion) in such a manner that the inlet fin 34 extends upstream of air along the flow of air and the outlet fin 46 is formed on the side surface on the air outlet side in such a manner that the outlet fin 46 extends downstream of air along the flow of air, a large heat transfer surface area can be provided and an improved heat exchange efficiency can be achieved as compared with a heat exchanger without the inlet and outlet fins 34 and 46. In addition, when the heat exchanger 20 is used as a evaporator or an exhaust heat recovery system, condensate water can be smoothly discharged downward and deposition of contaminants, dust and frost which could hamper the flow of air can be prevented to prevent decrease in heat exchange efficiency because the spacing between the inlet fins 34 of the adjacent heat-exchanger tubes 30 is greater than the spacing between the hollow tube portions. Moreover, since these improvements can be achieved simply by forming the inlet fins 34 and the outlet fins 46, increase in weight of the heat exchanger and increase in complexity of fabrication and assembly of the heat exchanger can be prevented. Furthermore, since the inlet fins 34 and the outlet fins 46 can be formed on heat-exchanger tubes 30 of a small heat exchanger in which the spacing between adjacent heat-exchanger tubes 30 is so small that corrugated fins cannot be attached to the heat-exchanger tubes 30, the heat exchange efficiency of such a small heat exchanger can be improved. Consequently, a small heat exchanger having high heat exchange efficiency can be implemented. Of course, a plurality of locations in the inner fin 50 are joined to the first tube member 32 and the second tube member 42, so that the deformation of the heat-exchanger tube 30 can be prevented even when pressure is applied to the fluorocarbon cooling medium (the first heat exchange medium) flowing through the heat-exchanger tube 30.

In the heat exchanger 20 of the embodiment, the first tube member 32 with the inlet fin 34 and the second tube member 42 with the outlet fin 46 are joined together to form each of the heat-exchanger tubes 30. However, as in a variation illustrated in FIG. 6, a first tube member 32B with an inlet fin 34B and an outlet fin 36B and a second tube member 42B with an inlet fin 44B and an outlet fin 46B may be joined together to form a heat-exchanger tube 30B. Alternatively, as illustrated in a variation in FIG. 7, a first tube member 32C with an inlet fin 34C and an outlet fin 36C and a second tube member 42C without inlet and outlet fins may be joined together to form a heat-exchanger tube 30C.

In the heat exchanger 20 of the embodiment, the inlet fin 34 and the outlet fin 46 are formed so as to extend upstream and downstream of air from the centers of the side surfaces of the hollow tube portion. However, the inlet fin and the outlet fin may be formed in any locations on the side surfaces of the hollow tube portion; it is only essential that the inlet and outlet fins are extended upstream and downstream of air. For example, as in a heat-exchanger tube 30D of a variation illustrated in FIG. 8, an inlet fin 34D and an outlet fin 36D may be formed so as to extend upstream and downstream of air from the oblong plane of the hollow tube portion. Alternatively, as in a heat-exchanger tube 30E of a variation illustrated in FIG. 9, an inlet fin 34E is formed so as to extend upstream of air from the oblong plane formed by the hollow tube portion of a second tube member 42E and an outlet fin 46E may be formed so as to extend downstream of air from the oblong plane formed by the hollow tube portion of a first tube member 32E.

In the heat exchanger 20 of the embodiment, the first tube member 32 with the inlet fin 34 and the second tube member 42 with the outlet fin 46 are joined together to form each of the heat-exchanger tubes 30. However, the inlet fin and the outlet fin may be omitted from the first tube member and the second tube member. For example, as in a variation illustrated in FIG. 10, a heat-exchanger tube 30F may be made up of a first tube member 32F and a second tube member 42F that have flanges 33F, 35F, 43F and 45F formed at open rectangular portions for joining and an inner fin 50F with an inlet fin 54F and an outlet fin 56F, and the first tube member 32F and the second tube member 42F may be joined together so as to sandwich the inner fin 50F. Flanges may be formed inward like flanges 33G, 35G, 43G and 45G of a first tube member 32G and a second tube member 42G of a heat-exchanger tube 30G of a variation in FIG. 11. Alternatively, as in a heat-exchanger tube 30H of a variation illustrated in FIG. 12, each of a first tube member 32H and a second tube member 42H may be formed into an open rectangular shape and an inlet fin 54H and an outlet fin 56H may be formed in an inner fin 50H so as to extend upstream and downstream of air from the oblong plane of the hollow tube portion.

Alternatively, as in a heat-exchanger tube 30J of a variation illustrated in FIG. 13, an inlet fin 54J and an outlet fin 56J may be formed as an integral flat plate, the flat plate having the inlet fin 54J and the outlet fin 56J may be sandwiched by a first tube member 32J and a second tube member 42J that have flanges 33J, 35J, 43J and 45J formed at open rectangular portions for joining, and inner fins 50J and 51J may be provided between the flat plate and the first and second tube member 32J and 42J. Alternatively, as in a heat-exchanger tube 30K of a variation illustrated in FIG. 14, an inlet fin 54K with an anti-slipout portion 55K and an outlet fin 56K with an anti-slipout portion 57K are sandwiched between flanges of a first tube member 32J and a second tube member 42J that are formed as open rectangular portions, and an inner fin 50K may be provided inside the hollow tube portion.

In the heat exchanger 20 of the embodiment, the inner fin 50 is provided inside the hollow tube portion of the heat-exchanger tube 30, the inner fin may be omitted from the hollow tube portion of the heat-exchanger tube 30. In this case, as in a heat-exchanger tube 30L of a variation illustrated in FIG. 15, a first tube member 32L and a second tube member 42L in which a plurality of grooves 37L and 47L are formed in an oblong plane by processing such as beading and a fin member 52L formed as an integral flat plate having an inlet fin 54J and an outlet fin 56J may be provided and the fin member 52L may be sandwiched by the first tube member 32L and the second tube member 42L. This can increase the heat transfer surface area of the heat-exchanger tube 30L and therefore can further improve heat exchange efficiency. In this case, the grooves 37L and 47L are formed preferably in such a manner that the bottoms of the grooves 37L faces the bottoms of the grooves 47L with the fin member 52L between them, and the bottoms of the grooves 37L and the bottoms of the grooves 47L are preferably brazed to the fin member 52L. This can prevent deformation of the heat-exchanger tube 30L when pressure is applied to the fluorocarbon cooling medium (the first heat exchange medium) flowing through the heat-exchanger tube 30L. Also in this case, as in a heat-exchanger tube 30M of a variation illustrated in FIG. 16, an inlet fin 54M with an anti-slipout portion 55M and an outlet fin 56M with an anti-slipout portion 57M may be sandwiched by a first tube member 32L and a second tube member 42L in which a plurality of grooves 37M and 47M are formed in an oblong plane.

In the heat exchanger 20 of the embodiment, the heat-exchanger tube 30 is configured with a single hollow tube portion, and an inlet fin 34 and an outlet fin 36 formed on both side surfaces of the hollow tube portion. However, a heat-exchanger tube may be formed with a plurality of hollow tube portions which are interconnected by fins. For example, as in a heat-exchanger tube 30N of a variation illustrated in FIG. 17, first tube members 32N and second tube members 42N that have inlet fins 34N and 44N, outlet fins 36N and 46N, and connecting fins 35N and 45N that connect two open rectangular portions may be joined together in such a manner that each inner fin 50BN is contained in each of the two rectangular parts.

In the heat exchanger 20 of the embodiment, the oblong plane of the hollow portion of the heat-exchanger tube 30 and the inlet fin 34 and the outlet fin 36 are even, flat surface. However, as in a heat-exchanger tube 30P of a variation illustrated in FIG. 18, one or more waves may be formed, where one or more series of V- or W-shaped peak lines 34 a, 46 a, each made up of a series of peaks of a wave (represented by alternate long and short dashed lines in FIG. 18), and one or more series of V- or W-shaped valley lines 34 b, 46 b, each made up of a series of valleys of a wave (represented by chain double-dashed lines in FIG. 18) may be formed. This increases the heat transfer surface area and therefore can increase the heat exchange efficiency. Since secondary streams along the flow of the first heat exchange medium and the flow of second heat exchange medium are produced near the wave surface, the heat exchange efficiency can be further improved.

While the hollow tube portion of each of the heat-exchanger tubes 30 in the heat exchanger 20 of the embodiment are formed into a rectangular shape, the hollow tube portion may be formed in any flattened shape. For example, as in a heat-exchanger tube 30Q of a variation illustrated in FIG. 19, the hollow tube portion may be formed into a hexagonal shape.

While the upper header 22 and the lower header 62 are attached at the upper ends and the lower ends of the plurality of heat-exchanger tubes 30 in the heat exchanger 20 of the embodiment, the upper header and the lower header may be omitted as in a heat exchanger 220 of a variation illustrated in FIGS. 20 to 22, for example. FIG. 20 is a diagram schematically illustrating a configuration of the heat exchanger 220 of the variation, FIG. 21 is a diagram schematically illustrating a configuration of a heat-exchanger tube 230, and FIG. 22 is a cross-sectional view of the heat-exchanger tube 230 taken along plane B-B of FIG. 21. As illustrated, the heat-exchanger tube 230 of the heat exchanger 220 of the variation includes a first tube member 232 having an inlet through hole 238 and an outlet through hole 239, which are simple holes formed in an upper center and a lower center of a hollow tube portion, and an inlet fin 234, a second tube member 242 having an inlet through hole 248 and an outlet through hole 249, which are formed in an upper center and a lower center of a hollow tube portion by burring, and an outlet fin 246, and an inner fin 250 which is inserted in the hollow tube portion. The heat exchanger 220 is formed by joining the inlet through hole 238 and the inlet through hole 248 of adjacent heat-exchanger tubes 230 together, joining the outlet through hole 239 and the outlet through hole 249 of adjacent heat-exchanger tubes 230 together, and attaching an inlet pipe 224 and an outlet pipe 264 to the inlet through hole 248 and the outlet through hole 249 of the heat-exchanger tube 230 at an end of the heat exchanger 220. In the heat exchanger 220 of the variation, the inner fin 250 is provided between a position slightly lower than the inlet through holes 238, 248 and a position slightly upper the outlet through holes 239, 249 in order to supply a first heat exchange medium (a fluorocarbon cooling medium) to each heat-exchanger tube 230. The heat exchanger 220 of the variation has the same functions as the heat exchanger 20 of the embodiment and therefore can achieve the same effects as the heat exchanger 20 of the embodiment. It should be noted that spacers may be provided near the inlet through holes 238, 248 and near the outlet through holes 239, 249 in order to add to the strength of portions of the heat-exchanger tubes 230 near the inlet through holes 238, 248 and near the outlet through holes 239, 249 of the heat-exchanger tube 230, and an offset fins may be provided. Furthermore, since the inlet through holes 238 and 248, the outlet through holes 239 and 249 can be formed in any of the heat-exchanger tubes 30B to 30Q of the variations illustrated in FIGS. 6 to 19 and joined together, a heat exchanger without upper and lower headers can achieve the same effect of the heat exchanger having any of the heat-exchanger tubes 30B to 30Q of the variations.

In the heat exchanger 20 of the embodiment, each of the heat-exchanger tubes 30 is formed from a 0.1-mm thick stainless-steel thin plate in such a manner that the oblong plane of the hollow tube has a width of 10.0 mm, the hollow tube has a thickness of 0.5 mm, and each of the inlet fin 34 and the outlet fin 46 has a length of 4.0 mm. However, the material and thickness of the thin plate from which the heat-exchanger tube 30 is formed, the sizes of the hollow tube, the inlet fin 34 and the outlet fin 46 are not limited to those given above and may be changed in accordance with the properties, pressure, temperate and the like of the first heat exchange medium flowing through the heat-exchanger tubes 30 and the properties, pressure, temperature and the like of the second heat exchange medium with which the first heat exchange medium exchanges heat. For example, if the pressure of the first heat exchange medium flowing through the heat-exchanger tubes 30 is high, the thickness of the stainless-steel thin plate may be 0.15 mm or 0.2 mm and the thickness of the hollow tube may be 0.6 mm, 0.8 mm, or 1.0 mm. If a small heat exchanger is formed from an aluminum thin plate, for example if a small heat exchanger is formed from an aluminum thin plate having a thickness of 0.25 mm, 0.3 mm, or 0.4 mm, the width of the oblong plane of the hollow tube may be 10.0 mm, 12 mm, or 15 mm, the thickness of the hollow tube may be 0.8 mm, 1.0 mm, 1.2 mm, 2.0 mm, or 3.0 mm, and the length of each of the inlet fin 34 and the outlet fin 46 may be 3.0 mm, 4.0 mm, 5.0 mm, or 6.0 mm. The spacing between adjacent heat-exchanger tubes 30 is not limited to 1.0 mm and may be determined on the basis of the properties, pressure, temperature and the like of the medium (air in the embodiment) flowing through between the adjacent heat-exchanger tubes 30. For example, the spacing between the adjacent heat-exchanger tubes 30 may be 0.5 mm, 1.5 mm, 2.0 mm, or 3.0 mm.

In the heat exchanger 20 of the embodiment, the inlet fin 34 extending upstream of air along the flow of air is formed on the side surface (the side surface of the hollow tube portion) on the air inlet side of the oblong hollow tube portion of the heat-exchanger tube 30 and the outlet fin 46 extending downstream of air along the flow of air is formed on the side surface on the air outlet side of the hollow tube portion. However, the outlet fin or the inlet fin may be omitted. In contrast, the outlet fin may be formed and the inlet fin may be omitted. In a heat exchanger equipped with any of these heat-exchanger tubes, large heat transfer surface area can be provided and the heat exchange efficiency can be improved as compared with a heat exchanger in which neither the inlet fin nor outlet fin is formed.

While the first and second tube members and the inner fins in the heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of its variations have been described only as being formed from a thin plate of a metal that has high heat conductivity (for example stainless-steel or aluminum), all of the first and second tube members and the inner fins may be formed from the same material or the inner fins may be formed from a material different from the material of the first and second tube members. For example, the first and second tube members may be made from stainless-steel, which has high strength, and the inner fins may be formed from aluminum, which has high heat conductivity.

The heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of its variations described above can be incorporated in a refrigeration cycle of an air conditioner such as a room air conditioner, an all-in-one air conditioning system, or a car air conditioner, or a refrigeration cycle in a refrigerating machine. For example, the heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of the variations can be used as a heat exchanger in which a cooling medium is flown through the heat-exchanger tubes and heat exchange between the cooling medium and air cools air. Accordingly, the heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of the variations described above can be used to implement a refrigeration cycle device such as a room air conditioner, an all-in-one air conditioning system, a car air conditioner, or a refrigerating machine. Furthermore, the heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of the variations described above can be implemented as a heat energy recovery device which recovers heat energy produced in an engine or a fuel cell. For example, the heat exchanger 20 of the embodiment and the heat exchangers 20B to 20Q and 220 of the variations can be used as a heat exchanger in which a heat exchange medium is flown through heat-exchanger tubes, an emission of an engine is flown between adjacent heat-exchanger tubes, and heat exchange between the emission and the heat exchange medium heats the heat exchange medium.

Correspondence between essential elements of the embodiment and the essential elements of the present invention that have been described in the section “Solution to Problem” will be described. The plurality of heat-exchanger tubes 30 in the embodiment corresponds to “a plurality of heat-exchanger tubes”, the fluorocarbon cooling medium corresponds to “a first heat exchange medium”, air corresponds to “a second heat exchange medium”, the inlet fins 34 correspond to “inlet fins”, and the outlet fins 46 correspond to “outlet fins”.

It should be noted that the correspondence between the essential elements of the embodiment and the essential elements of the present invention described in the section “Solution to Problem” is an example for specifically explaining a mode for carrying out the present invention described in the section “Solution to Problem” and is not intended to limit the elements of the present invention described in the section “Solution to Problem”. That is, the invention described in the section “Solution to Problem” should be interpreted on the basis of the description in that section and the embodiment is only illustrative of the present invention described in the section “Solution to Problem”.

While a mode for carrying out the present invention has been described with respect to embodiment thereof, the present invention is not limited to that embodiment. It would be understood that the present invention can be embodied in various other modes without departing form the spirit of the present invention.

The technique of the present invention is preferably applied to the manufacturing industries of the heat exchanger.

REFERENCE SIGN LIST

-   1 a heat exchanger, 22 an upper header, 24 an inlet, 30, 30B-30Q,     230 a heat-exchanger tube, 32, 32B-32Q, 232 a first tube member,     33F-33J, 35F-35J flanges, 34, 34B-34Q an inlet fin, 36B-36N an     outlet fin, 37L,37M grooves, 42, 42B-42Q a second tube member,     43F-43J, 45F-45J flanges, 44B-44N an inlet fin, 46, 46B-46Q an     outlet fin, 47L, 27M grooves, 50, 50E-50K, 51J an inner fin, 52L a     fin member, 54F-54M an inlet fin, 55K,55M an anti-slipout portion,     56F-56M an outlet fin, 57K,57M an anti-slipout portion, 62 a lower     header, and 64 an outlet.

CITATION LIST Patent Literature

-   Patent Literature 1: Japanese Patent Laid-Open No. 2001-167782 -   Patent Literature 2: Japanese Patent Laid-Open No. 2007-232339 

1. A heat exchanger, comprising: a plurality of heat-exchanger tubes which are made of a metal into flattened hollow tubes and are arranged in parallel to one another in such a manner that oblong planes face one another and performs heat exchange by using a first heat exchange medium flowing through the plurality of heat-exchanger tubes and a second heat exchange medium flowing between the plurality of heat-exchanger tubes in a direction orthogonal to the first heat exchange medium; wherein the plurality of heat-exchanger tubes has inlet fins extending upstream along a flow of the second heat exchange medium from a side surface on the inlet side of the second heat exchange medium.
 2. The heat exchanger in accordance with claim 1, wherein the inlet fins are integral with a member that constitutes the heat-exchanger tubes.
 3. The heat exchanger in accordance with claim 1, wherein the heat-exchanger tubes include an inner fin inside the tubes and the inlet fin is integral with the inner
 4. The heat exchanger in accordance with claim 1, wherein a wavelike ridges and grooves where a series of “V” shape peaks and valleys of a wave runs viewed from the upstream side of the flow of the second heat exchange medium is formed in the oblong planes of the inlet fins and/or the heat-exchanger tubes.
 5. The heat exchanger in accordance with claim 1, wherein the plurality of heat-exchanger tubes have outlet fins extending downstream along the flow of the second heat exchange medium from a side surface on the outlet side of the second heart exchange medium.
 6. The heat exchanger in accordance with claim 5, wherein the outlet fin is integral with a member that constitute each heat-exchanger tube.
 7. The heat exchanger in accordance with claim 1, wherein the plurality of heat-exchanger tubes has outlet fins extending upstream along a flow of the second heat exchange medium from a side surface on the outlet side of the second heat exchange medium; and the heat-exchanger tubes include an inner fin inside the tubes and the inlet fin or the outlet fin is integral with the inner fin.
 8. A heat exchanger, comprising: a plurality of heat-exchanger tubes which are made of a metal into flattened hollow tubes and are arranged in parallel to one another in such a manner that oblong planes face one another and performs heat exchange by using a first heat exchange medium flowing through the plurality of heat-exchanger tubes and a second heat exchange medium flowing between the plurality of heat-exchanger tubes in a direction orthogonal to the first heat exchange medium; wherein the plurality of heat-exchanger tubes has outlet fins extending downstream along a flow of the second heat exchange medium from a side surface on the outlet side of the second heat exchange medium.
 9. The heat exchanger in accordance with claim 1, wherein the heat-exchanger tubes are formed to have a thickness of less than or equal to 3 mm and are arranged in parallel to one another with a regular spacing of less than or equal to 3 mm between adjacent heat-exchanger tubes.
 10. A refrigeration cycle device with application of the heat exchanger in accordance with claim
 1. 11. A heat energy recovery device with application of the heat exchanger in accordance with claim
 1. 